The Applicant proposes an improvement to monoclonal antibody technology through the generation of transgenic mice engineered to facilitate flow cytometric isolation and cloning of specific antigen-reactive plasmacytes. Monoclonal antibodies (mAbs) are arguably the most important biological reagents used in biomedical research, diagnostics, and therapeutics, and the demand for them is increasing exponentially. MAbs are secreted from hybridoma cells that are fusions of antibody-producing lymphocytes (B cells) and immortal myeloma cells. Abeome's patented Direct Selection of Hybridoma (DiSHTM) technology represents a significant improvement to hybridoma technology. Through the use of a novel myeloma parent, genetically engineered for the constitutive expression of transgenic Ig-receptor proteins Ig-alpha and Ig-beta, all of the derived B cell hybridomas express a complete B cell receptor (BCR) complex on the cell surface. Specific hybridomas of interest are subsequently selected and cloned by Fluorescent Activated Cell Sorting (FACS) after labeling the BCR with fluorescent antigen. There remain, however, limitations within hybridoma technology that prevent efficient sampling of the full repertoire of plasmacytes, the lymphocytes producing the highest affinity antibodies. Herein, we are proposing an extension of DiSH technology that will allow the Targeted Selection of Plasmacytes (TSP). The TSP concept is founded on the transgenic expression of Ig-receptor proteins Ig-alpha and Ig-beta in engineered mice. TSP technology will result in surface expression of the BCR complex directly on antibody-secreting plasmacytes in mice, which can then be isolated using FACS based on expression of the BCR complex and its reaction with fluorescently labeled antigen. This Phase I project proposes to establish a colony of TSP transgenic mice, demonstrate expression of the transgene, and show that these mice are immunologically functional and thereby accomplish a major milestone towards a significant commercially feasible improvement in monoclonal antibody technology. PUBLIC HEALTH RELEVANCE: Monoclonal antibodies represent some of the most successful research and diagnostic tools available to scientists and clinicians. More importantly, their high specificity and sensitivity, coupled with favorable pharmacokinetics and safety, make them highly attractive therapeutic agents. The Applicant proposes the generation of transgenic mice that would greatly facilitate the isolation of antigen-specific plasma cells directly from immunized animals, thereby improving the speed and efficiency of obtaining monoclonal antibodies. The proposed project represents a major milestone towards the ultimate goal of generating transgenic mice that eliminate the requirement for the currently required myeloma-B cell fusion step.